The present invention relates to a device for temporarily closing bottles containing champagne or similar products, that is to say, liquids under pressure.
It is known that champagne and sparkling wines are fermented directly in the bottle in two or more different stages of production. The time between one stage and the next may be quite long.
At the end of some of these stages, the bottles have to be opened and, therefore, temporary closing devices are used. These devices must prevent the liquid and gas from escaping from the bottle during the entire production stage, which, in some cases, may last several years. During this time, the temporary closing device is subjected to pressures of as much as 6 to 8 BAR by the gas that develops inside the bottle.
Usually, a temporary closing device used for this purpose comprises a substantially cylindrical, hollow stopper closed at the top by a transversal surface that extends past the lateral surface of the cylinder, in such a way as to create a supporting surface. The stopper is made of a synthetic material and is pressed into the neck of the bottle until its supporting surface comes into contact with the rim of the bottle mouth.
A metal sealing capsule is then fitted over the stopper to keep the latter in place. The edge of the capsule, usually of the crown type, is designed to be clamped over the outer annular edge of the bottle neck.
Attached to the inside face of the capsule, between the latter and the stopper inserted in the bottle neck, there is a seal which is designed to press against the annular end face of the bottle neck and against the transversal surface of the stopper. The seal, acting in conjunction with the stopper, is designed to prevent the gas and liquid from escaping for the required length of time.
In known temporary closing devices (see publication EP-594494), the edge of the seal has two diverging annular lips which move apart on opposite sides so as to cover the annular end face of the bottle neck, thus sealing the bottle.
To prevent the stopper from being pushed outwards along the bottle neck by the pressure inside the bottle, thus diminishing the effectiveness of the seal, the latter has a plurality of equally-spaced bosses around the edge of it, close to the two lips. Once the capsule has been applied, the bosses act on the transversal surface of the stopper, close to the edge, thus keeping the stopper in position and preventing stresses that would diminish the effectiveness of the remaining part of the seal applied to the glass.
However, devices of this kind have some disadvantages.
The bosses, which are designed to hold the stopper in place, complicate the structure of the seal, making it more difficult to manufacture.
Moreover, the position of the bosses around the edge of the transversal surface of the stopper creates breaks in the contact with the surface and does not prevent the internal gas pressure from causing a swelling in the transversal surface over the opening in the bottle neck. This swelling deforms the lateral surface of the stopper, which tends to converge towards the axis of the stopper itself close to the end of it that faces the inside of the bottle.
This in turn causes the lateral surfaces of the stopper to become detached from the inside surface of the bottle neck, allowing gas and liquid to leak towards the seal and lessening the effectiveness of the seal, especially considering the fact that the temporary closing device has to remain on for long periods of time.
The aim of the present invention is to overcome the above mentioned drawbacks.